Using your watch as a compass

[thirdcrank]

Why would anybody in Essex want to know the way oop North?

[The utility cyclist]

Why would anybody in Essex want to know the way oop North?

The question should be why wouldn't they be wanting to find their way out of Essex!

[Mick F]

Heading Up North by train return costs a fortune.
Cheaper to drive there and back and pay for the petrol.

Why, for goodness sake!

[Jdsk]

That's because you were following the wrong instructions! Jdsk was responding to my OP enquiry about how to do this in the southern hemisphere. The OP tells you how to do it in Essex.

Well spotted... I didn't understand the problem.

Jonathan

[simonhill]

I used Jonathan's method because he invited me to do so (see previous posts).

I find it strange that in Nik's method for the Northern hemisphere you point the hour hand at the sun, but in J's for the Southern one, you point the 12/top towards the sun. Can someone explain why the difference please. Personally, I don't see any difference in being South of the tropics, except that your bisect will point South instead of North.

I am happy to accept that Nik's method works. It is Jonathon's that I was querying - North or South of the tropics.

I would think that the 'correct method' will work in the Tropics, you just have to know if the sun is South or North of you. Might be a bit tricky if it is overhead.

[Jdsk]

I would think that the 'correct method' will work in the Tropics, you just have to know if the sun is South or North of you. Might be a bit tricky if it is overhead.

It isn't just that bit of extra information that you need, the low latitude and high declination conspire against accuracy:
https://academic.oup.com/astrogeo/article/52/3/3.12/187095

Jonathan

[simonhill]

Johnathan, is your first post correct?

[Jdsk]

Yes, you point the noon mark on the face of the watch towards the sun, and bisect the angle to the hour hand.

But it's the noon mark that you need to use in both cases... that isn't always twelve.

And it's much more complicated if you're in the tropics.

I think so, but please don't hold back... : - )

Jonathan

[simonhill]

I thought it should be the hour hand that you point to the sun, not the noon point.

Edit Now at home and Mr Google agrees it should be the noon point in the Southern hemisphere. Query withdrawn.

[nirakaro]

Can someone explain why the difference please. Personally, I don't see any difference in being South of the tropics, except that your bisect will point South instead of North.

The hour hand of your watch moves from left to right. The sun moves across the sky from left to right, in the northern hemisphere. In the southern hemisphere, it moves from right to left, so the method has to be different. Or something.

[simonhill]

The noon hand to the sun in the Southern hemisphere clearly works (ex numerous google searches), so I won't worry about why it does. It will give me something to think about on one of those long boring days in the saddle once I'm allowed to tour again. Who knows, maybe even down under so I can do my own experiments.

[st599_uk]

At night, you can use Ursa Major as a watch.

[st599_uk]

Heading Up North by train return costs a fortune.
Cheaper to drive there and back and pay for the petrol.

Why, for goodness sake!

Government transport policy.

For example in Germany/Czechia I did Berlin - Leipzig, Leipzig - Colditz, Colditz - Dresden, Dresden - Prague. Al four tickets came to £85 paying on the day. Similar distance in the UK would be well over £300 full price.

[wearwell]

At night, you can use Ursa Major as a watch.

Only if you have a nautical almanac handy, or printout therefrom, or a very good memory!

Navigating with a watch - if you can see the sun at all you don't need to fiddle with the watch except to tell the time. 12noon GMT it's approx due south, 6am it's due east 6pm due west. Interpolate for a good enough guess for times in between. Add an hour to correct for BST. This is good enough for ordinary navigating in middling latitudes but near impossible if you are near the equator or happen to cycling in polar regions.
Can be handy if you are on minor roads and have misread the map - e.g.sudden realisation that the sun should be on your left not on the right! etc.

[st599_uk]

At night, you can use Ursa Major as a watch.

Only if you have a nautical almanac handy, or printout therefrom, or a very good memory!
Navigating with a watch - if you can see the sun at all you don't need to fiddle with the watch except to tell the time. 12midday GMT it's approx due south, 6am it's due east 6pm due west. Interpolate for a good enough guess for times in between. Add an hour to correct for BST. This is good enough for ordinary navigating.
Can be handy if you are on minor roads and have misread the map - e.g.sudden realisation that the sun should be on your left not on the right! etc.

Not at all. It's easier than the sun and watch method.

https://www.timeanddate.com/astronomy/t ... stars.html